Drawing apparatus



Dfw-15, 1969 A. M. J. MARLBQROUGH ETAL 3,483,593

DRAWING APPARATUS Filed March 25, 1966 2 Sheets-Sheet 1 Ey 9 MM.

Dec. 16, 1969 A. M, J. MARLBOROUGH ETAL 3,483,593

DRAWING APPARATUS Filed March 25, 1966 '2 Sheets-Sheet 2 9 l 50 32 E: 5r

l o pff-? 29 l/ o v f l L l nb n 1o I 9 le 17 s4 ss 2a 5 r2 FsG.2

/A/I/E/V'UFS United States Patent O US. Cl. 18-1 3 Claims ABSTRACT OF'IHlE DISCLGSURE In a yarn drawing apparatus of the type including afeed roll, heated plate and a draw roll the yarn is moved to and froacross the face of the plate by a reciprocating guide in order to reducethe formation of ridges of partially decomposed yarn finish componentson the plate and to spread the wear over the plate.

This invention relates to the drawing of synthetic thermoplasticfilaments and in particular to an improvement in the apparatus used forsaid drawing wherein the apparatus includes feed and draw rolls and aheated plate.

Drawing, or elongation of synthetic thermoplastic filaments in the solidstate, is required to orient the macromolecules comprising the filamentsthereby imparting strength to the filaments. Several types of drawingapparatus have been devised for carrying out the elongation step. Onecommonly used method is to feed the undrawn yarn around a rst roller,usually referred to as the feed roller, then over and in contact with astationary heated plate to a second roller, usually referred to as thedraw roller, rotating at a higher peripheral speed than the firstroller. The first roller is usually heated to facilitate elongation ofthe filaments and sufficient wraps of filamentary yarn are taken aroundthe feed roll such that substantially all the drawing takes place beforethe yarn leaves the feed roll. The hot plate usually serves tofacilitate the completion of any remaining elongation and to heat setthe yarn thereby reducing the shrinkage of the drawn yarn, whensubsequently subjected to heat treatment, the ratio of the peripheralspeed of the draw roller to that of the feed roller is termed the drawratio.

vWe have now found that the continuous operation of a drawframe of theforegoing type is greatly facilitated and the useful life of thehotplate is increased, by incorporating in the drawframe means formoving the yarn to and fro across the face of the hotplate during thedrawing operation.

According to the present invention we provide drawing apparatus forsynthetic thermoplastic filamentary yarns comprising a yarn supply,means for feeding the yarn from the yarn supply to a feed roll or rolls,a draw roll or rolls rotating at a higher peripheral speed than saidfeed roll or rolls and a heated plate intermediate the feed and drawrolls, wherein means is also provided for moving the yarn to and froacross the face of the heated plate.

In drawing synthetic thermoplastic yarn it is customary to coat the yarnwith a lubricating and/or antistatic finish before drawing. This finishis usually organic in nature, being composed of vegetable or mineraloils or other organic substances. During drawing of the coated yarn overthe heated plate intermediate the feed and draw rolls some of the finishis removed and tends to collect on the heated surface just outside thetrack of the yarn across the surface, where it is subject to continuousbak- ICC ing which partially decomposes the components 0f the finishforming a hard, abrasive crust or ridge on the surface. If the movingyarn contacts this crust or ridge lilament breakage and also possiblyyarn breakage may result leading to poor quality of the drawn yarn orinterruption of the drawing process. By means of the present inventionformation of the ridges of partially decomposed finish components issubstantially reduced, for movement of the yarn across the face of theheated surface has the effect of smoothing out the deposits as fast asthey are formed. An important advantage accruing to the use of thepresent invention is the spreading of the wear on the heated surfacemore evenly over a larger part of the surface thereby increasing theuseful life of the surface. One method which has been suggested toincrease the life of the hot plate is to mount the heated plate so thatit may be intermittently moved sideways with respect to the yarnexposing a new track for the yarn to take across the plate. However thismethod is clumsy in use requiring frequent attention by the operator,which is cumbersome in modern drawframes which may incorporate a hundredor more spindles, and does not make full use of the plate surface aseach movement must be sufficient to pass the accumulated ridge of finishresidue. Another method which has been used but which is mechanicallycomplex and expensive to produce is a rotatable multisurface plate asdescribed in British patent specification No. 960,977. By means of thepresent invention both spin finish build-up on the plate issubstantially reduced and wear is spread evenly over the Whole Workingsurface of the plate in a simple manner.

Movement of the yarn across the face of the heated plate may be obtainedby means of any one of Several types of yarn traverse device, as forexample cam and follower to which a yarn guide is attached directly orthrough a suitable mechanical linkage, or by pneumatic means, by meansof which the yarn is caused to reciprocate over a short stroke. Thetraverse device may be placed before the feed roll or intermediate thefeed roll and the heated surface. We prefer to place it before the feedroll in order that only undrawn yarn, which is less subject to damagethan drawn yarn, should come in contact with the traverse device.

In some known types of drawing machines for synthetic thermoplasticyarns wherein the means for feeding yarn from the yarn supply to thefeed roll or rolls is a pair of cooperating rolls one of which has arubber or similar high friction resilient surface, a traverse device ofconstant short stroke is placed before the feeding means. In this casehowever, due to the pressure at the nip of the c0- operating rolls,which is necessary to ensure uniform supply of yarn to the drawingmachine, movement to and fro of the yarn is not transmitted further thanthe nip 0f these rolls and has no effect upon wear of or build-up oforganic residues upon the heated plate. Consequently for satisfactoryoperation of such drawing machines it is desirable to incorporate anadditional traversing means according to this invention.

The kind of reciprocating motion imparted to the yarn `may be simple orcomplex and we prefer to use a two component motion wherein a primaryreciprocation is superimposed upon a slower secondary reciprocation. Inthis way, `wear of the heated surface over long periods takes the formof a smooth concave track in the surface. This is preferred to the formof Wear obtained with a simple single reciprocation wherein a trackhaving sharper edges (at the extremes of the traverse stroke) is formed.

This in an embodiment of the invention We have placed anhydraulic-pneumatic traverse device before the feed roll, said devicecausing the yarn to reciprocate at a speed of 3 cycles per minute with astroke of 0.25 inch (0.625 cm.). Superimposed on this primaryreciprocation is a secondary reciprocation of 0.125 inch (0.32 cm.)stroke at a speed of 3 cycles per hour. The extremes of the primary andseecondary strokes are arranged to overlap slightly in order that nishresidues should not buildup unduly at the edges of the track and thatwear on the plate should be as smooth as possible.

A preferred embodiment of the invention is illustrated in theaccompanying drawings wherein;

FIGURE 1 is a diagrammatic representation of one position of amultiposition drawframe.

FIGURE 2 is a diagrammatic representation of an hydraulic-pneumaticmeans for producing an oscillatory motion and FIGURE 3 is a diagrammaticrepresentation of a linkage translating the oscillatory motion toreciprocating motion of a yarn guide.

Referring to FIGURE 1 the position comprises a yarn feeding meansconsisting of two cooperating rolls 1 and 2, the upper one 1, having aresilient rubber surface, a yarn guide 3, for moving the yarn to and froaccording to the invention, positioned between the yarn feeding means 1,2 and a heated feed roll 4, whereon drawing of the yarn is to takeplace. A heated metal plate 5, is situated below the feed roll 4, andbefore a draw roll 6, which may or may not be heated. Finally a yarnguide 7 and yarn collection means 8 are included to complete theposition.

In operation undrawn yarn Y, is fed from the nip between rolls 1 and 2,by `way of the guide 3 to the feed roll 4 around which it is taken anumber of times such that drawing is substantially complete when theyarn leaves roll 4 and passes to the hotplate 5 whereon any small amountof drawing is completed and heat setting is effected, the yarn thenpassing to and around the draw roll 6. The draw roll 6 rotates at ahigher peripheral speed than the feed roll 4 and thereby provides therequired drawing tension, a suflicient number of turns being takenaround the roll 6 such that yarn slippage is substantially prevented.Drawn, set yarn from the draw roll 6 is guided by guide 7 to thecollection means 8 which may be a ring-rail type of collector whichinserts twist in the collecting yarn.

Referring now to FIGURE 2, apparatus for producing a complex oscillatorymotion comprises a compresed air supply control valve 9, Which controlsthe air supply to a junction 10, whence air is supplied to a doubleacting valve 11, and to two single acting spring loaded valves 12 and13. Valves 12 and 13 are attached in spaced apart relationship to acarriage 14 which is slidably engaged inside rail portions 15, of a baseplate 16.

A cam 17 is located within a cavity in carriage 14 and is turned in astepwise manner by means of a needle clutch 18 actuated by a lever arm19 Which is pivotally attached by rod 20 to arm 21. Arm 21 oscillatesabout bearing 22 and to one end is ixed a hammer head 23 and to theother end is attached a piston rod 24 connected to pneumatic andhydraulic pistons inside a pneumatichydraulic valve 25. Valve 25consists of a double acting pneumatic section 26 and a hydraulic section27. Air is supplied to both sides of a piston in the pneumatic section26 from the valve 11, and the hydraulic section 27, which also containsa piston on the common shaft 24, is connected through regulating valves28, 29 and one way valves 30, 31 to a reservoir 32 the internal pressurewithin which is regulated by means of a spring loaded piston 33.

A shaft (not shown), connected to arm 21 at the bearing 22, transfersthe oscillatory motion of arm 21 through the linkage of FIGURE 3 to theyarn guide 3.

In operation the apparatus is set in motion by opening control valve 9which opening may be effected manually or electrically, as for example,by using a solenoid operated control valve 9. Compresed air is thensupplied to juntion and passes through valve 11 to either the left orright hand side of the piston in the pneumatic section 26 of valve 25pushing it towards the opposite end of its stroke. This movement causesthe shaft 24 to be pushed outwards or inwards with a movement which isdamped by the passage of oil from section 27 through a regulator valve28 or 29, through reservoir 32 and back through the second regulator 29or 28 to the other side of the piston in the hydraulic section 27 ofvalve 25. Movement of shaft 24 causes arm 21 to move about bearing 22 sothat head 23 contacts valve 12 or 13 momentarily opening it. Opening ofvalve 12 or 13 causes a pulse of compressed air supplied to the valvefrom junction 10, to enter valve 11 and the piston therein to bedisplaced from one end to the other, this displacement in turn causingthe air supplied from junction 10 to be passed to the opposite side ofthe piston in section 26 of valve 25 from that to which it was initiallysupplied thus reversing the cycle of events.

The primary oscillation of the shaft attached to arm 21 at bearing 22 isthus obtained by the movement of head 23 to and fro between successivecontacts with valves 12 and 13. However the overall motion of this shaftis complex for as arm 21 moves in one direction (either to left orright) the needle clutch 18 actuated through rod 20 and lever 19, causesa small increment of rotation of cam 17 and a small sliding movement ofcarriage 14. This movement of carriage 14 alters the position of valves12 and 13 with respect to the bearing 22 and hence the point at whichthe head 23 contacts said valves. This has the effect of combining withthe primary oscillation a secondary movement, of very much longerperiod. Movement of arm 21 in the opposite direction does not cause theneedle clutch to move cam 17 as the action of the clutch isunidirectional.

The period of oscillation maybe adjusted by means of the regulators 28and 29 and piston 33 acts as a buffer for oil lpulses.

Referring now to FIGURE 3 as hereinbefore described an oscillatorymotion is imparted to arm 21 about the bearing 22. This motion is givento la shaft 34 supported from the frame of the drawing machine by abracket. 35, to which shaft a cam, 36, is non-rotatably attached.Depending from the ybracket 35 is an arm 37 pivotally attached thereto,to the free end of which a bar 38 is xed in substantially parallelrelationship to shaft 34. T o bar 38, the yarn guide 3, and a camfollower 39 are fixed so as to move therewith. The follower 39 isattached to bar 38 opposite to cam 36 and cooperates therewith, cams 36and follower 39 being urged together contact by means of a spring 40attached at one end to the bracket 35 and at the other to the arm 37.

Any synthetic thermoplastic yarn which may be oriented and strengthenedby drawing may be drawn using drawing `apparatus according to thisinvention. Thus a process for drawing synthetic thermoplastic lamentaryyarns comprises feeding the yarn from a supply thereof to a feed roll orrolls, which roll or rolls may be heated or unheated, then over and incontact with a stationary hot plate of suicient length to provide therequired contact time, to a `draw roll or rolls rotated at a higherperipheral speed than said feed roll or rolls to a yarn collectingmeans, characterised in that the yarn, is caused to reciprocate with asimple or complex motion of the foregoing type across the hot plate.

What we claim is:

1. In drawing apparatus for synthetic thermoplastic lamentary yarns ofthe type including a yarn supply, means for feeding y-arn from saidsupply, a feed roll, a draw roll rotating at a higher peripheral speedthan said feed roll and a heated plate intermediate the feed and drawrolls over which the yarn passes longitudinally of -itself duringoperation, the improvement which comprises means for reducing theformation on said heated plate of ridges of partially decomposed yarnfinish components, said means including a yarn guide and reciproeatingdrive means for imparting to said yarn guide a two component actioncomprising a primary reciprocation superimposed upon a slower secondaryreciprocation in a manner such that the extremes of primary andsecondary reciprocation overlap slightly.

2. Drawing apparatus according to claim 1 wherein the means for movingthe yarn to and fro is operable at a point intermediate the yarn feedingmeans and the feed roll.

3. Drawing apparatus according to claim 1 wherein the means for movingthe yarn to and fr0 is operable at a point intermediate the feed rolland heated plate.

References Cited UNITED STATES PATENTS 2,199,411 5/1940 Lewis 28-62 X2,272,666 2/1942 Hoifman 264--167 2,278,888 4/1942 Lewis 264-167 X2,289,232 7/1942 Babcock 264-290 X 2,920,345 1/1960 Dyer 264-167 X2,975,474 3/1961 Smith 264-167 X 3,302,385 2/1967 Ruddell et al. 57-157FOREIGN PATENTS Great Britain. Great Britain. Japan.

Japan. France. Japan.

IULIUS FROME, Primary Examiner I. H. WOO, Assistant Examiner U.S. C1.X.R.

